First Time In still finding my way

[askalot]

Hi All,

I have embraked on a scratch built cnc router and i have made the frame and started on the linear rail supports. but the main concern that plagues my in the design phase is the choice of axis drive methods.

The methods i have looked at is :-
1, lead screw
2, Ball Screw
3, Power tranmission belts ( cogged Belt )
4, Rack and Pinion

All of the above have pro's and con's but as a newbee to this side of things i am at the cross roads of a decision based on mass, inertia and acceleration none of which i have just yet haven't got that far in the build.

So i am looking for some information on choices which have been made by others in hope that it may give me a better understanding of what i need to consider and include in the next level of design phase.

Thanks in advance

Askalot

[harryn]

One of the more interesting questions is - can you really do it with just one method ? After a great deal of effort, I am finding that no matter what I do, I am constrained so that my machine is ending up with 2 drive methods. (belt x 2 and rack and pinion x 1)

I didn't really consider ball screws after I studied the cost, but frankly, they were all getting into the same range.

Shipping large, precision items to Australia can force your decision a bit as well, making belts attractive sometimes even if the parts are not the lowest cost.

There is a linear motion FAQ (above) that might help, and you might consider searching around from users in Australia and New Zeland for ideas.